yz450f flywheel weight

so gray have we come to any conclusions yet? they just sent my flywheel from TT yesterday so it won't be here t'ill weds so i can weigh them,i'm gonna be a little ticked off if its only a +1 :D
Funny you should ask. I just got the response I was waiting for from some who should know: Doug Dubach. It would seem I had some BAD INFORMATION :):D

Whatever the rotating mass the marketing types were talking about that was supposedly increased (if it happened at all) it was NOT the flywheel. Or the cranks either, for that matter. One of the staff at Dr.D remembers that reference, too, but has no idea what it means. I put that together with something else I heard and I have, just as you said, been misleading people with the incorrect assertion that the '04 flywheel was heavier than the '03. They're not.

I hate making mistakes like that, but you can't just bury them in the back yard, either, can you?

BTW, I'm pretty sure the flywheel is going to weigh more than 2.2 pounds, so look around for a bigger scale. :)

On another note, I'm trying out a GYT-R 5oz myself this week. After riding the Off-road I picked up, I decided it was a little more than I wanted. I got this one cheap and we'll see about it next.

GrayRacer and MountainMan, I just spent a little time going over the moving parts on the 2003 and 2004 in the online parts catalog. The parts that have different part numbers are as follows:

On the CLUTCH page:

2003-(5) 5TA-16371-00-00 BOSS, CLUTCH. 2004 -(5) 5TA-16371-02-00 BOSS, CLUTCH

2003-(23) 5TA-16384-00-00 PLATE, SEAT. 2004-(23) 5TA-16384-01-00 PLATE, SEAT


2003-(9) 5TA-11455-00-00 SHAFT 1. 2004-(9) 5TA-11455-11-00 SHAFT 1

2003-(11) 5TA-11531-00-00 GEAR, BALANCE WEIGHT. 2004-(11) 5TA-11531-01-00 GEAR, BALANCE WEIGHT

On the ELECTRICAL page:

2003-(3) 5TA-82310-00-00 IGNITION COIL ASSY. 2004-(3) 5TA-82310-10-00 IGNITION COIL ASSY

I included the the coil because it could influence power delivery. I stopped at this point because I got tired of staring at part numbers. As stated before the flywheels (rotor assemblies) are the same.

I'm thinking that parts 9 and 11 above are increased in mass for 2004 and because they are directly off the crank it results in different power delivery. The coil could have an effect too and that would be easy to test. Part 23 on above was probably changed to address the clutch problems the 2003 may have had. Part 5, the clutch boss, may have been changed for the same reason and if heavier would effect power delivery too. Not as much as the parts just of the crank though.

Dan450, I hate to say it, but I think MountanMan may be right on that placebo effect you may be feeling. Were you able to dig up the part number?

I've been waiting for a while on this flywheel subject. Today I'll start throwing money at it. I'm starting with GYT-5TA97-50-00. :)

Dan450, I hate to say it, but I think MountanMan may be right on that placebo effect you may be feeling. We you able to dig up the part number?
He basically has to be, since we've discovered the two are tthe same :)
I've been waiting for a while on this flywheel subject. Today I'll start throwing money at it. I'm starting with GYT-5TA97-50-00. :)
That's the lighter of the two that Dubach says equals about 5oz added weight. If you ride MX, you'll like it.

hey gray, i noticed you've changed your sig to the 5oz so i'm guessin' its on. is there a noticeable diff or prefferance 5 or 7. i'm gonna be right in the middle with the 6oz(if it ever gets here) i think i'm more in need of some inertia in the motor than traction as its got plenty of traction with the rekluse. but i've noticed a couple times it's stalled because it didn't feel as though it had enough fww to make it to the next stroke.hopefully the fw will help :)

I noticed and am curious too as I'm waiting for my 5oz to show up.

i'm pretty sure the triple beam i've got goes to a kilo,so thats plenty :thumbsup:it'll be over a week before it gets here :)

What's up with the triple beam? :)

leftover from the good ol'days :)

I want to smooth the power out in a 2003 yz450f someone recommended a zip-ty 8oz. flywheel weight. Is this a good idea for someone who mostly rides and races motocross?


IMO, the 8oz is a better choice. It also depends on how much you want to soften the BEAST. I first changed to a D.D 4oz (he did not have a 6oz in stock). The 4oz did not help enough for my taste. (I'm an old man, 45, race Int, that set up still had arm wrenching PULL).

My ride was more manageable when I installed a 15t, that change CALM THE BEAST!!!!!!!!!!!!! and I've raced with it ever since. Plus on most tracks, I was riding in 2nd gear only, with shifting to 3rd maybe once a lap........... I LOVED THAT SET UP, but then I'm not a Kid, that enjoyed the 2 stroke feel.....................

Good Luck it's an AWESOME ride



thats a pretty bad stutter ya got there :)

(To The Top) Hoping Grayracer would see the thread is still alive.

well,i put my +6 trail tech on last night, and yes it was 167 grams more,so if my conversion is correct thats 1 gram short of +6 :) the quality of this thing is just short of amazing :D and i gotta say +6 is the way to go,its just enough to smooth it out and make it dig but yet not enough to drag the motor down :D so thats 3 thumbs up for the trailtech +6 :D:D:D sorry i've been calling it race tech and its really trail tech :)

(To The Top) Hoping Grayracer would see the thread is still alive.
Sorry, I never caught it on page one, I guess.

I had a 7oz that I bought, but then had an opportunity to get a 5oz. I was skeptical about whether it would be enough different from the 4oz Dr.D to tell, but it is (and isn't). What I found compared to the 5oz was that the engine "felt" very little different from the 4oz. Still very quick revving and explosive, something like a big bore two stroke, really, but the bike behaved differently. I tried it out in an area where I ride a lot, so I was familiar with the traction. In places where grabbing the throttle hard would produce major wheelspin before, it would bite, lift the wheel, and take off instead. That's where it showed up, improved traction, and acceleration very little different if at all.

The 7oz was just too heavy, although if you do a lot of trail stuff or woods riding, either the 7 or the Dr.D 8 will help quite a bit. It lugs much more willingly with the extra weight.

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